Accident Overview
On June 18, 2016, about 1235 eastern daylight time, a Beech P35 airplane, registration N112MB, ditched in Block Island Sound after a total loss of engine power near Westerly, Rhode Island. The private pilot received minor injuries. Visual meteorological conditions prevailed, and a visual flight rules flight plan was filed but not activated for the personal flight. The airplane was owned and operated by the pilot under Title 14 Code of Federal Regulations Part 91. The flight originated from Francis S. Gabreski Airport (FOK), Westhampton Beach, New York, with an intended destination of Taunton Municipal Airport (TAN), Taunton, Massachusetts.
Pilot Account
In an interview with a Federal Aviation Administration (FAA) Inspector, the pilot stated that while en route, he attempted to reduce the manifold pressure, but it did not respond. He then heard a "loud bang," followed by oil covering the windscreen, and the engine lost total power. The pilot reported that the propeller rpm "was all over the place" prior to the total loss of engine power. He ditched about 2 miles west of Westerly State Airport (WST), Westerly, Rhode Island. After landing in the water, the pilot egressed without incident, and the airplane sank.
Aircraft and Engine Details
The airplane was recovered and examined. The wings, empennage, and fuselage sustained substantial damage during the accident sequence. A hole was noted in the top of the engine crankcase. According to FAA records, the airplane was manufactured in 1962 and powered by a 260-hp Continental Motors, Inc., IO-470-N21B reciprocating engine. The most recent annual inspection was completed on December 29, 2015, at a recorded tachometer reading of 2,812 hours, airframe total time of 5,186 hours, and engine time since major overhaul of 99 hours. The pilot indicated that at the time of the accident, the engine had accumulated 109 hours of engine time since major overhaul.
Oil Filter Adapter Examination
The engine was equipped with an F&M Enterprises Inc. (model C6LC-L) oil filter adapter, which was not original equipment but could be installed under FAA Supplemental Type Certificate (STC) number SE09356SC. The oil filter adapter installation was completed on December 1, 2011, at the same time as the engine overhaul. The manufacturer's installation instructions specified that the adapter body be torqued to 65 ft lbs and retorqued after 10 hours of operation. The adapter required one fiber gasket and one copper crush gasket. Maintenance guidance indicated that at each annual or 100-hour inspection, the mechanic was to inspect the oil filter adapter for oil seepage, safety wire, and security, and record results in the logbook. Gaskets were to be replaced anytime the adapter was removed and reinstalled, and at 300 hours or 3 years, whichever came first. The most recent recorded maintenance on the oil filter adapter was on August 25, 2012, at an engine time since major overhaul of 40 hours.
Engine Disassembly Findings
An examination of the engine revealed that the oil filter adapter tightening breakaway torque was 13.58 ft lbs, and the loosening torque was less than 13.33 ft lbs, as the torque wrench would not register any lower torque. The fiber gasket between the adapter and the engine was torn and partially extruded from the adapter. After removal, the fiber gasket was found torn in one location, and the crush deformation was not symmetrical around the gasket. Additionally, the Nos. 2 and 4 connecting rods had separated from the crankshaft. All connecting rod journals exhibited thermal damage and signatures consistent with lubrication distress.